PHP extension not found :: GMP

I try to install this on my Strato Webserver. But i get the error:

"PHP extension not found :: GMP"

Can someone tell me, what i need to do? Do I have to install / activate GMP first? If yes how? Unfortunately, I'm not very familiar with Linux. :-(

[BITKarBo]

Same issue but fixed by enabling extension=GMP 😂
You just don't have GMP enabled in your php.config

I'm do stupid for that...
I put the php.ini with following content into the rankme folder on the server:

extension=gmp

I haven't access to the origin php.ini from strato at the root directory. In this case you should but a php.ini into that directory you want it effected to. So i put the php.ini into the rankme folder. But it dosn't have any impact.

Could you maybe send me your complete php.ini or tell me what i need to do aswell?

[silvioxpt]

1 - sudo apt install php-gmp
2 - add php_gmp.so in php.ini